Distributed signal field for communications within multiple user, multiple access, and/or MIMO wireless communications

ABSTRACT

Distributed signal field for communications within multiple user, multiple access, and/or MIMO wireless communications. In accordance with wireless communications, a signal (SIG) field employed within such packets is distributed or partitioned into at least two separate signal fields (e.g., SIG A and SIG B) that are located in different portions of the packet. A first of the SIG fields includes information that may be processed and decoded by all wireless communication devices, and a second of the SIG fields includes information that is specific to one or more particular wireless communication devices (e.g., a specific wireless communication device or a specific subset of the wireless communication devices). 
     The precise locations of the at least first and second SIG fields within a packet may be varied, including placing a second of the SIG fields (e.g., including user-specific information) adjacent to and preceding a data field in the packet.

CROSS REFERENCE TO RELATED PATENTS/PATENT APPLICATIONS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. §120 as a continuation of U.S. Utility application Ser. No.14/089,939, entitled “Distributed signal field for communications withinmultiple user, multiple access, and/or MIMO wireless communications”,filed Nov. 26, 2013, pending, and scheduled subsequently to be issued asU.S. Pat. No. 9,107,099 on Aug. 11, 2015 (as indicated in an ISSUENOTIFICATION mailed from the USPTO on Jul. 22, 2015), which is acontinuation of U.S. Utility application Ser. No. 12/852,859, entitled“Distributed signal field for communications within multiple user,multiple access, and/or MIMO wireless communications,” filed Aug. 9,2010, now U.S. Pat. No. 8,599,804, issued on Dec. 3, 2013, which claimspriority pursuant to 35 U.S.C. §119(e) to U.S. Provisional ApplicationNo. 61/232,316, entitled “WLAN next generation PHY header options,”filed Aug. 7, 2009; U.S. Provisional Application No. 61/240,285,entitled “WLAN next generation PHY header options,” filed Sep. 7, 2009;U.S. Provisional Application No. 61/250,531, entitled “WLAN nextgeneration PHY header options,” filed Oct. 11, 2009; and U.S.Provisional Application No. 61/255,232, entitled “WLAN next generationPHY header options,” filed Oct. 27, 2009,” all of which are herebyincorporated herein by reference in their entirety and made part of thepresent U.S. Utility Patent Application for all purposes.

INCORPORATION BY REFERENCE

The following U.S. Utility Patent Applications are hereby incorporatedherein by reference in their entirety and are made part of the presentU.S. Utility Patent Application for all purposes:

1. U.S. Utility patent application Ser. No. 12/796,655, entitled “Groupidentification and definition within multiple user, multiple access,and/or MIMO wireless communications,” filed on Jun. 8, 2010, pending.

2. U.S. Utility patent application Ser. No. 12/816,352, entitled“Carrier sense multiple access (CSMA) for multiple user, multipleaccess, and/or MIMO wireless communications,” filed on 06-15-2010, nowU.S. Pat. No. 8,804,495, issued on Aug. 8-12, 2014.

3. U.S. Utility patent application Ser. No. 12/817,118, entitled“Scheduled clear to send (CTS) for multiple user, multiple access,and/or MIMO wireless communications,” filed on Jun. 16, 2010, now U.S.Pat. No. 8,582,485, issued on Nov. 12, 2013.

4. U.S. Utility patent application Ser. No. 12/821,094, entitled “Mediumaccessing mechanisms within multiple user, multiple access, and/or MIMOwireless communications,” filed on Jun. 22, 2010, now U.S. Pat. No.8,441,975, issued on May 14, 2013.

The following IEEE standard is hereby incorporated herein by referencein its entirety and is made part of the present U.S. Utility PatentApplication for all purposes:

1. IEEE 802.11 -2007, “IEEE Standard for Informationtechnology—Telecommunications and information exchange betweensystems—Local and metropolitan area networks—Specific requirements; Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications,” IEEE Computer Society, IEEE Std 802.11™-2007, (Revisionof IEEE Std 802.11-1999), 1232 pages.

BACKGROUND OF THE INVENTION Technical Field of the Invention

The invention relates generally to communication systems; and, moreparticularly, it relates to formatting of a distributed signal field forcommunications within multiple user, multiple access, and/or MIMOwireless communications.

Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11x,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, et cetera communicates directlyor indirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the receiver is coupled to theantenna and includes a low noise amplifier, one or more intermediatefrequency stages, a filtering stage, and a data recovery stage. The lownoise amplifier receives inbound RF signals via the antenna andamplifies them. The one or more intermediate frequency stages mix theamplified RF signals with one or more local oscillations to convert theamplified RF signal into baseband signals or intermediate frequency (IF)signals. The filtering stage filters the baseband signals or the IFsignals to attenuate unwanted out of band signals to produce filteredsignals. The data recovery stage recovers raw data from the filteredsignals in accordance with the particular wireless communicationstandard.

As is also known, the transmitter includes a data modulation stage, oneor more intermediate frequency stages, and a power amplifier. The datamodulation stage converts raw data into baseband signals in accordancewith a particular wireless communication standard. The one or moreintermediate frequency stages mix the baseband signals with one or morelocal oscillations to produce RF signals. The power amplifier amplifiesthe RF signals prior to transmission via an antenna.

Typically, the transmitter will include one antenna for transmitting theRF signals, which are received by a single antenna, or multiple antennae(alternatively, antennas), of a receiver. When the receiver includes twoor more antennae, the receiver will select one of them to receive theincoming RF signals. In this instance, the wireless communicationbetween the transmitter and receiver is a single-output-single-input(SISO) communication, even if the receiver includes multiple antennaethat are used as diversity antennae (i.e., selecting one of them toreceive the incoming RF signals). For SISO wireless communications, atransceiver includes one transmitter and one receiver. Currently, mostwireless local area networks (WLAN) that are IEEE 802.11, 802.11a,802,11b, or 802.11g employ SISO wireless communications.

Other types of wireless communications includesingle-input-multiple-output (SIMO), multiple-input-single-output(MISO), and multiple-input-multiple-output (MIMO). In a SIMO wirelesscommunication, a single transmitter processes data into radio frequencysignals that are transmitted to a receiver. The receiver includes two ormore antennae and two or more receiver paths. Each of the antennaereceives the RF signals and provides them to a corresponding receiverpath (e.g., LNA, down conversion module, filters, and ADCs). Each of thereceiver paths processes the received RF signals to produce digitalsignals, which are combined and then processed to recapture thetransmitted data.

For a multiple-input-single-output (MISO) wireless communication, thetransmitter includes two or more transmission paths (e.g., digital toanalog converter, filters, up-conversion module, and a power amplifier)that each converts a corresponding portion of baseband signals into RFsignals, which are transmitted via corresponding antennae to a receiver.The receiver includes a single receiver path that receives the multipleRF signals from the transmitter. In this instance, the receiver usesbeam forming to combine the multiple RF signals into one signal forprocessing.

For a multiple-input-multiple-output (MIMO) wireless communication, thetransmitter and receiver each include multiple paths. In such acommunication, the transmitter parallel processes data using a spatialand time encoding function to produce two or more streams of data. Thetransmitter includes multiple transmission paths to convert each streamof data into multiple RF signals. The receiver receives the multiple RFsignals via multiple receiver paths that recapture the streams of datautilizing a spatial and time decoding function. The recaptured streamsof data are combined and subsequently processed to recover the originaldata.

With the various types of wireless communications (e.g., SISO, MISO,SIMO, and MIMO), it would be desirable to use one or more types ofwireless communications to enhance data throughput within a WLAN. Forexample, high data rates can be achieved with MIMO communications incomparison to SISO communications.

However, most WLAN include legacy wireless communication devices (i.e.,devices that are compliant with an older version of a wirelesscommunication standard). As such, a transmitter capable of MIMO wirelesscommunications should also be backward compatible with legacy devices tofunction in a majority of existing WLANs.

Therefore, a need exists for a WLAN device that is capable of high datathroughput and is backward compatible with legacy devices.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver.

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention.

FIG. 13 is a diagram illustrating an embodiment of a wirelesscommunication device, and clusters, as may be employed for supportingcommunications with at least one additional wireless communicationdevice.

FIG. 14 is a diagram illustrating an embodiment of a frame format thatmay be used in conjunction with a wireless communication device such asa WLAN device.

FIG. 15 is a diagram illustrating an embodiment of possible frameformats, corresponding to single user multiple input multiple output(SU-MIMO), that may be used in conjunction with a wireless communicationdevice such as a WLAN device.

FIG. 16 is a diagram illustrating an embodiment of a possible frameformat, corresponding to multi-user multiple input multiple output(MU-MIMO) and particularly in accordance with a resolvable operationalmode (e.g., resolvable VHT-LTFs mode), that may be used in conjunctionwith a wireless communication device such as a WLAN device.

FIG. 17 is a diagram illustrating an embodiment of possible frameformats, corresponding to multi-user multiple input multiple output(MU-MIMO) and particularly in accordance with a non-resolvableoperational mode (e.g., non-resolvable VHT-LTFs mode), that may be usedin conjunction with a wireless communication device such as a WLANdevice.

FIG. 18A and FIG. 18B are diagrams illustrating embodiments of a frameformat, showing a distributed SIG field, that may be used in conjunctionwith a wireless communication device such as a WLAN device.

FIG. 19 is a diagram illustrating an embodiment of a frame format,having a unified preamble as applicable for both SU and MU operationalmodes (including both a MU resolvable operational mode and a MUnon-resolvable operational mode) in which a common set of precoding(steering) weights being applied throughput a portion of the multi-userpacket for each user.

FIG. 20 is a diagram illustrating an embodiment of a format of a firstSIG field (e.g., VHT-SIG-A) as may be employed in accordance with adistributed SIG field.

FIG. 21 is a diagram illustrating an embodiment of constellations as maybe employed for at least two orthogonal frequency division multiplexing(OFDM) symbols that may be employed in accordance with a first SIG field(e.g., VHT-SIG-A) as may be employed in accordance with a distributedSIG field.

FIG. 22 is a diagram illustrating an embodiment of a format of a secondSIG field (e.g., VHT-SIG-B) as may be employed in accordance with adistributed SIG field.

FIG. 23 is a diagram illustrating an alternative embodiment of a formatof a first SIG field (e.g., VHT-SIG-A) as may be employed in accordancewith a distributed SIG field.

FIG. 24 is a diagram illustrating an alternative embodiment of a formatof a second SIG field (e.g., VHT-SIG-B) as may be employed in accordancewith a distributed SIG field.

FIG. 25A, FIG. 25B, FIG. 26A, FIG. 26B, FIG. 27A, and FIG. 27B arediagrams illustrating various embodiments of methods for operating oneor more wireless communication devices.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system 10 that includes a plurality of base stationsand/or access points 12-16, a plurality of wireless communicationdevices 18-32 and a network hardware component 34. The wirelesscommunication devices 18-32 may be laptop host computers 18 and 26,personal digital assistant hosts 20 and 30, personal computer hosts 24and 32 and/or cellular telephone hosts 22 and 28. The details of anembodiment of such wireless communication devices is described ingreater detail with reference to FIG. 2.

The base stations (BSs) or access points (APs) 12-16 are operablycoupled to the network hardware 34 via local area network connections36, 38 and 40. The network hardware 34, which may be a router, switch,bridge, modem, system controller, et cetera provides a wide area networkconnection 42 for the communication system 10. Each of the base stationsor access points 12-16 has an associated antenna or antenna array tocommunicate with the wireless communication devices in its area.Typically, the wireless communication devices register with a particularbase station or access point 12-14 to receive services from thecommunication system 10. For direct connections (i.e., point-to-pointcommunications), wireless communication devices communicate directly viaan allocated channel.

Typically, base stations are used for cellular telephone systems (e.g.,advanced mobile phone services (AMPS), digital AMPS, global system formobile communications (GSM), code division multiple access (CDMA), localmulti-point distribution systems (LMDS), multi-channel-multi-pointdistribution systems (MMDS), Enhanced Data rates for GSM Evolution(EDGE), General Packet Radio Service (GPRS), high-speed downlink packetaccess (HSDPA), high-speed uplink packet access (HSUPA and/or variationsthereof) and like-type systems, while access points are used for in-homeor in-building wireless networks (e.g., IEEE 802.11, Bluetooth, ZigBee,any other type of radio frequency based network protocol and/orvariations thereof). Regardless of the particular type of communicationsystem, each wireless communication device includes a built-in radioand/or is coupled to a radio. Such wireless communication devices mayoperate in accordance with the various aspects of the invention aspresented herein to enhance performance, reduce costs, reduce size,and/or enhance broadband applications.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device that includes the host device 18-32 and anassociated radio 60. For cellular telephone hosts, the radio 60 is abuilt-in component. For personal digital assistants hosts, laptop hosts,and/or personal computer hosts, the radio 60 may be built-in or anexternally coupled component. For access points or base stations, thecomponents are typically housed in a single structure.

As illustrated, the host device 18-32 includes a processing module 50,memory 52, radio interface 54, input interface 58 and output interface56. The processing module 50 and memory 52 execute the correspondinginstructions that are typically done by the host device. For example,for a cellular telephone host device, the processing module 50 performsthe corresponding communication functions in accordance with aparticular cellular telephone standard.

The radio interface 54 allows data to be received from and sent to theradio 60. For data received from the radio 60 (e.g., inbound data), theradio interface 54 provides the data to the processing module 50 forfurther processing and/or routing to the output interface 56. The outputinterface 56 provides connectivity to an output display device such as adisplay, monitor, speakers, et cetera such that the received data may bedisplayed. The radio interface 54 also provides data from the processingmodule 50 to the radio 60. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, et cetera via the input interface 58 or generate the dataitself. For data received via the input interface 58, the processingmodule 50 may perform a corresponding host function on the data and/orroute it to the radio 60 via the radio interface 54.

Radio 60 includes a host interface 62, a baseband processing module 64,memory 66, a plurality of radio frequency (RF) transmitters 68-72, atransmit/receive (T/R) module 74, a plurality of antennae 82-86, aplurality of RF receivers 76-80, and a local oscillation module 100. Thebaseband processing module 64, in combination with operationalinstructions stored in memory 66, execute digital receiver functions anddigital transmitter functions, respectively. The digital receiverfunctions, as will be described in greater detail with reference to FIG.11B, include, but are not limited to, digital intermediate frequency tobaseband conversion, demodulation, constellation demapping, decoding,de-interleaving, fast Fourier transform, cyclic prefix removal, spaceand time decoding, and/or descrambling. The digital transmitterfunctions, as will be described in greater detail with reference tolater Figures, include, but are not limited to, scrambling, encoding,interleaving, constellation mapping, modulation, inverse fast Fouriertransform, cyclic prefix addition, space and time encoding, and/ordigital baseband to IF conversion. The baseband processing modules 64may be implemented using one or more processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. The memory 66 may be a single memory device or a pluralityof memory devices. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. Note that when the processing module 64 implementsone or more of its functions via a state machine, analog circuitry,digital circuitry, and/or logic circuitry, the memory storing thecorresponding operational instructions is embedded with the circuitrycomprising the state machine, analog circuitry, digital circuitry,and/or logic circuitry.

In operation, the radio 60 receives outbound data 88 from the hostdevice via the host interface 62. The baseband processing module 64receives the outbound data 88 and, based on a mode selection signal 102,produces one or more outbound symbol streams 90. The mode selectionsignal 102 will indicate a particular mode as are illustrated in themode selection tables, which appear at the end of the detaileddiscussion. For example, the mode selection signal 102, with referenceto table 1 may indicate a frequency band of 2.4 GHz or 5 GHz, a channelbandwidth of 20 or 22 MHz (e.g., channels of 20 or 22 MHz width) and amaximum bit rate of 54 megabits-per-second. In other embodiments, thechannel bandwidth may extend up to 1.28 GHz or wider with supportedmaximum bit rates extending to 1 gigabit-per-second or greater. In thisgeneral category, the mode selection signal will further indicate aparticular rate ranging from 1 megabit-per-second to 54megabits-per-second. In addition, the mode selection signal willindicate a particular type of modulation, which includes, but is notlimited to, Barker Code Modulation, BPSK, QPSK, CCK, 16 QAM and/or 64QAM. As is further illustrated in table 1, a code rate is supplied aswell as number of coded bits per subcarrier (NBPSC), coded bits per OFDMsymbol (NCBPS), data bits per OFDM symbol (NDBPS).

The mode selection signal may also indicate a particular channelizationfor the corresponding mode which for the information in table 1 isillustrated in table 2. As shown, table 2 includes a channel number andcorresponding center frequency. The mode select signal may furtherindicate a power spectral density mask value which for table 1 isillustrated in table 3. The mode select signal may alternativelyindicate rates within table 4 that has a 5 GHz frequency band, 20 MHzchannel bandwidth and a maximum bit rate of 54 megabits-per-second. Ifthis is the particular mode select, the channelization is illustrated intable 5. As a further alternative, the mode select signal 102 mayindicate a 2.4 GHz frequency band, 20 MHz channels and a maximum bitrate of 192 megabits-per-second as illustrated in table 6. In table 6, anumber of antennae may be utilized to achieve the higher bit rates. Inthis instance, the mode select would further indicate the number ofantennae to be utilized. Table 7 illustrates the channelization for theset-up of table 6. Table 8 illustrates yet another mode option where thefrequency band is 2.4 GHz, the channel bandwidth is 20 MHz and themaximum bit rate is 192 megabits-per-second. The corresponding table 8includes various bit rates ranging from 12 megabits-per-second to 216megabits-per-second utilizing 2-4 antennae and a spatial time encodingrate as indicated. Table 9 illustrates the channelization for table 8.The mode select signal 102 may further indicate a particular operatingmode as illustrated in table 10, which corresponds to a 5 GHz frequencyband having 40 MHz frequency band having 40 MHz channels and a maximumbit rate of 486 megabits-per-second. As shown in table 10, the bit ratemay range from 13.5 megabits-per-second to 486 megabits-per-secondutilizing 1-4 antennae and a corresponding spatial time code rate. Table10 further illustrates a particular modulation scheme code rate andNBPSC values. Table 11 provides the power spectral density mask fortable 10 and table 12 provides the channelization for table 10.

It is of course noted that other types of channels, having differentbandwidths, may be employed in other embodiments without departing fromthe scope and spirit of the invention. For example, various otherchannels such as those having 80 MHz, 120 MHz, and/or 160 MHz ofbandwidth may alternatively be employed such as in accordance with IEEETask Group ac (TGac VHTL6).

The baseband processing module 64, based on the mode selection signal102 produces the one or more outbound symbol streams 90, as will befurther described with reference to FIGS. 5-9 from the output data 88.For example, if the mode selection signal 102 indicates that a singletransmit antenna is being utilized for the particular mode that has beenselected, the baseband processing module 64 will produce a singleoutbound symbol stream 90. Alternatively, if the mode select signalindicates 2, 3 or 4 antennae, the baseband processing module 64 willproduce 2, 3 or 4 outbound symbol streams 90 corresponding to the numberof antennae from the output data 88.

Depending on the number of outbound streams 90 produced by the basebandmodule 64, a corresponding number of the RF transmitters 68-72 will beenabled to convert the outbound symbol streams 90 into outbound RFsignals 92. The implementation of the RF transmitters 68-72 will befurther described with reference to FIG. 3. The transmit/receive module74 receives the outbound RF signals 92 and provides each outbound RFsignal to a corresponding antenna 82-86.

When the radio 60 is in the receive mode, the transmit/receive module 74receives one or more inbound RF signals via the antennae 82-86. The T/Rmodule 74 provides the inbound RF signals 94 to one or more RF receivers76-80. The RF receiver 76-80, which will be described in greater detailwith reference to FIG. 4, converts the inbound RF signals 94 into acorresponding number of inbound symbol streams 96. The number of inboundsymbol streams 96 will correspond to the particular mode in which thedata was received (recall that the mode may be any one of the modesillustrated in tables 1-12). The baseband processing module 64 receivesthe inbound symbol streams 90 and converts them into inbound data 98,which is provided to the host device 18-32 via the host interface 62.

In one embodiment of radio 60 it includes a transmitter and a receiver.The transmitter may include a MAC module, a PLCP module, and a PMDmodule. The Medium Access Control (MAC) module, which may be implementedwith the processing module 64, is operably coupled to convert a MACService Data Unit (MSDU) into a MAC Protocol Data Unit (MPDU) inaccordance with a WLAN protocol. The Physical Layer ConvergenceProcedure (PLCP) Module, which may be implemented in the processingmodule 64, is operably coupled to convert the MPDU into a PLCP ProtocolData Unit (PPDU) in accordance with the WLAN protocol. The PhysicalMedium Dependent (PMD) module is operably coupled to convert the PPDUinto a plurality of radio frequency (RF) signals in accordance with oneof a plurality of operating modes of the WLAN protocol, wherein theplurality of operating modes includes multiple input and multiple outputcombinations.

An embodiment of the Physical Medium Dependent (PMD) module, which willbe described in greater detail with reference to FIGS. 10A and 10B,includes an error protection module, a demultiplexing module, and aplurality of direction conversion modules. The error protection module,which may be implemented in the processing module 64, is operablycoupled to restructure a PPDU (PLCP (Physical Layer ConvergenceProcedure) Protocol Data Unit) to reduce transmission errors producingerror protected data. The demultiplexing module is operably coupled todivide the error protected data into a plurality of error protected datastreams The plurality of direct conversion modules is operably coupledto convert the plurality of error protected data streams into aplurality of radio frequency (RF) signals.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 2 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the baseband processing module 64 and memory 66may be implemented on a second integrated circuit, and the remainingcomponents of the radio 60, less the antennae 82-86, may be implementedon a third integrated circuit. As an alternate example, the radio 60 maybe implemented on a single integrated circuit. As yet another example,the processing module 50 of the host device and the baseband processingmodule 64 may be a common processing device implemented on a singleintegrated circuit. Further, the memory 52 and memory 66 may beimplemented on a single integrated circuit and/or on the same integratedcircuit as the common processing modules of processing module 50 and thebaseband processing module 64.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter 68-72, or RF front-end, of the WLAN transmitter. The RFtransmitter 68-72 includes a digital filter and up-sampling module 75, adigital-to-analog conversion module 77, an analog filter 79, andup-conversion module 81, a power amplifier 83 and a RF filter 85. Thedigital filter and up-sampling module 75 receives one of the outboundsymbol streams 90 and digitally filters it and then up-samples the rateof the symbol streams to a desired rate to produce the filtered symbolstreams 87. The digital-to-analog conversion module 77 converts thefiltered symbols 87 into analog signals 89. The analog signals mayinclude an in-phase component and a quadrature component.

The analog filter 79 filters the analog signals 89 to produce filteredanalog signals 91. The up-conversion module 81, which may include a pairof mixers and a filter, mixes the filtered analog signals 91 with alocal oscillation 93, which is produced by local oscillation module 100,to produce high frequency signals 95. The frequency of the highfrequency signals 95 corresponds to the frequency of the outbound RFsignals 92.

The power amplifier 83 amplifies the high frequency signals 95 toproduce amplified high frequency signals 97. The RF filter 85, which maybe a high frequency band-pass filter, filters the amplified highfrequency signals 97 to produce the desired output RF signals 92.

As one of average skill in the art will appreciate, each of the radiofrequency transmitters 68-72 will include a similar architecture asillustrated in FIG. 3 and further include a shut-down mechanism suchthat when the particular radio frequency transmitter is not required, itis disabled in such a manner that it does not produce interferingsignals and/or noise.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver. Thismay depict any one of the RF receivers 76-80. In this embodiment, eachof the RF receivers 76-80 includes an RF filter 101, a low noiseamplifier (LNA) 103, a programmable gain amplifier (PGA) 105, adown-conversion module 107, an analog filter 109, an analog-to-digitalconversion module 111 and a digital filter and down-sampling module 113.The RF filter 101, which may be a high frequency band-pass filter,receives the inbound RF signals 94 and filters them to produce filteredinbound RF signals. The low noise amplifier 103 amplifies the filteredinbound RF signals 94 based on a gain setting and provides the amplifiedsignals to the programmable gain amplifier 105. The programmable gainamplifier further amplifies the inbound RF signals 94 before providingthem to the down-conversion module 107.

The down-conversion module 107 includes a pair of mixers, a summationmodule, and a filter to mix the inbound RF signals with a localoscillation (LO) that is provided by the local oscillation module toproduce analog baseband signals. The analog filter 109 filters theanalog baseband signals and provides them to the analog-to-digitalconversion module 111 which converts them into a digital signal. Thedigital filter and down-sampling module 113 filters the digital signalsand then adjusts the sampling rate to produce the digital samples(corresponding to the inbound symbol streams 96).

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data. This diagram shows a method for converting outbounddata 88 into one or more outbound symbol streams 90 by the basebandprocessing module 64. The process begins at Step 110 where the basebandprocessing module receives the outbound data 88 and a mode selectionsignal 102. The mode selection signal may indicate any one of thevarious modes of operation as indicated in tables 1-12. The process thenproceeds to Step 112 where the baseband processing module scrambles thedata in accordance with a pseudo random sequence to produce scrambleddata. Note that the pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1.

The process then proceeds to Step 114 where the baseband processingmodule selects one of a plurality of encoding modes based on the modeselection signal. The process then proceeds to Step 116 where thebaseband processing module encodes the scrambled data in accordance witha selected encoding mode to produce encoded data. The encoding may bedone utilizing any one or more a variety of coding schemes (e.g.,convolutional coding, Reed-Solomon (RS) coding, turbo coding, turbotrellis coded modulation (TTCM) coding, LDPC (Low Density Parity Check)coding, etc.).

The process then proceeds to Step 118 where the baseband processingmodule determines a number of transmit streams based on the mode selectsignal. For example, the mode select signal will select a particularmode which indicates that 1, 2, 3, 4 or more antennae may be utilizedfor the transmission. Accordingly, the number of transmit streams willcorrespond to the number of antennae indicated by the mode selectsignal.

The process then proceeds to Step 120 where the baseband processingmodule converts the encoded data into streams of symbols in accordancewith the number of transmit streams in the mode select signal. This stepwill be described in greater detail with reference to FIG. 6.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5. This diagram shows a method performed by thebaseband processing module to convert the encoded data into streams ofsymbols in accordance with the number of transmit streams and the modeselect signal. Such processing begins at Step 122 where the basebandprocessing module interleaves the encoded data over multiple symbols andsubcarriers of a channel to produce interleaved data. In general, theinterleaving process is designed to spread the encoded data overmultiple symbols and transmit streams. This allows improved detectionand error correction capability at the receiver. In one embodiment, theinterleaving process will follow the IEEE 802.11(a) or (g) standard forbackward compatible modes. For higher performance modes (e.g., IEEE802.11(n), the interleaving will also be done over multiple transmitpaths or streams.

The process then proceeds to Step 124 where the baseband processingmodule demultiplexes the interleaved data into a number of parallelstreams of interleaved data. The number of parallel streams correspondsto the number of transmit streams, which in turn corresponds to thenumber of antennae indicated by the particular mode being utilized. Theprocess then continues to Steps 126 and 128, where for each of theparallel streams of interleaved data, the baseband processing modulemaps the interleaved data into a quadrature amplitude modulated (QAM)symbol to produce frequency domain symbols at Step 126. At Step 128, thebaseband processing module converts the frequency domain symbols intotime domain symbols, which may be done utilizing an inverse fast Fouriertransform. The conversion of the frequency domain symbols into the timedomain symbols may further include adding a cyclic prefix to allowremoval of intersymbol interference at the receiver. Note that thelength of the inverse fast Fourier transform and cyclic prefix aredefined in the mode tables of tables 1-12. In general, a 64-pointinverse fast Fourier transform is employed for 20 MHz channels and128-point inverse fast Fourier transform is employed for 40 MHzchannels.

The process then proceeds to Step 130 where the baseband processingmodule space and time encodes the time domain symbols for each of theparallel streams of interleaved data to produce the streams of symbols.In one embodiment, the space and time encoding may be done by space andtime encoding the time domain symbols of the parallel streams ofinterleaved data into a corresponding number of streams of symbolsutilizing an encoding matrix. Alternatively, the space and time encodingmay be done by space and time encoding the time domain symbols ofM-parallel streams of interleaved data into P-streams of symbolsutilizing the encoding matrix, where P=2M. In one embodiment theencoding matrix may comprise a form of:

$\quad\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \ldots & C_{{2M} - 1} & C_{2M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \ldots & {- C_{2M}^{*}} & {C_{{2M} - 1}\;}\end{bmatrix}$

The number of rows of the encoding matrix corresponds to M and thenumber of columns of the encoding matrix corresponds to P. Theparticular symbol values of the constants within the encoding matrix maybe real or imaginary numbers.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data. FIG. 7 is a diagram of one method that may be utilizedby the baseband processing module to encode the scrambled data at Step116 of FIG. 5. In this method, the encoding of FIG. 7 may include anoptional Step 144 where the baseband processing module may optionallyperform encoding with an outer Reed-Solomon (RS) code to produce RSencoded data. It is noted that Step 144 may be conducted in parallelwith Step 140 described below.

Also, the process continues at Step 140 where the baseband processingmodule performs a convolutional encoding with a 64 state code andgenerator polynomials of G₀=133₈ and G₁=171₈ on the scrambled data (thatmay or may not have undergone RS encoding) to produce convolutionalencoded data. The process then proceeds to Step 142 where the basebandprocessing module punctures the convolutional encoded data at one of aplurality of rates in accordance with the mode selection signal toproduce the encoded data. Note that the puncture rates may include ½, ⅔and/or ¾, or any rate as specified in tables 1-12. Note that, for aparticular, mode, the rate may be selected for backward compatibilitywith IEEE 802.11(a), IEEE 802.11(g), or IEEE 802.11(n) raterequirements.

FIG. 8 is a diagram of another encoding method that may be utilized bythe baseband processing module to encode the scrambled data at Step 116of FIG. 5. In this embodiment, the encoding of FIG. 8 may include anoptional Step 148 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data. It isnoted that Step 148 may be conducted in parallel with Step 146 describedbelow.

The method then continues at Step 146 where the baseband processingmodule encodes the scrambled data (that may or may not have undergone RSencoding) in accordance with a complimentary code keying (CCK) code toproduce the encoded data. This may be done in accordance with IEEE802.11(b) specifications, IEEE 802.11(g), and/or IEEE 802.11(n)specifications.

FIG. 9 is a diagram of yet another method for encoding the scrambleddata at Step 116, which may be performed by the baseband processingmodule. In this embodiment, the encoding of FIG. 9 may include anoptional Step 154 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data.

Then, in some embodiments, the process continues at Step 150 where thebaseband processing module performs LDPC (Low Density Parity Check)coding on the scrambled data (that may or may not have undergone RSencoding) to produce LDPC coded bits. Alternatively, the Step 150 mayoperate by performing convolutional encoding with a 256 state code andgenerator polynomials of G₀=561₈ and G₁=753₈ on the scrambled data thescrambled data (that may or may not have undergone RS encoding) toproduce convolutional encoded data. The process then proceeds to Step152 where the baseband processing module punctures the convolutionalencoded data at one of the plurality of rates in accordance with a modeselection signal to produce encoded data. Note that the puncture rate isindicated in the tables 1-12 for the corresponding mode.

The encoding of FIG. 9 may further include the optional Step 154 wherethe baseband processing module combines the convolutional encoding withan outer Reed Solomon code to produce the convolutional encoded data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter. This may involve the PMD module of a WLAN transmitter. InFIG. 10A, the baseband processing is shown to include a scrambler 172,channel encoder 174, interleaver 176, demultiplexer 170, a plurality ofsymbol mappers 180-184, a plurality of inverse fast Fourier transform(IFFT)/cyclic prefix addition modules 186-190 and a space/time encoder192. The baseband portion of the transmitter may further include a modemanager module 175 that receives the mode selection signal 173 andproduces settings 179 for the radio transmitter portion and produces therate selection 171 for the baseband portion. In this embodiment, thescrambler 172, the channel encoder 174, and the interleaver 176 comprisean error protection module. The symbol mappers 180-184, the plurality ofIFFT/cyclic prefix modules 186-190, the space time encoder 192 comprisea portion of the digital baseband processing module.

In operations, the scrambler 172 adds (e.g., in a Galois Finite Field(GF2)) a pseudo random sequence to the outbound data bits 88 to make thedata appear random. A pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1 toproduce scrambled data. The channel encoder 174 receives the scrambleddata and generates a new sequence of bits with redundancy. This willenable improved detection at the receiver. The channel encoder 174 mayoperate in one of a plurality of modes. For example, for backwardcompatibility with IEEE 802.11(a) and IEEE 802.11(g), the channelencoder has the form of a rate ½ convolutional encoder with 64 statesand a generator polynomials of G₀=133₈ and G₁=171₈. The output of theconvolutional encoder may be punctured to rates of ½, ⅔, and ¾ accordingto the specified rate tables (e.g., tables 1-12). For backwardcompatibility with IEEE 802.11(b) and the CCK modes of IEEE 802.11(g),the channel encoder has the form of a CCK code as defined in IEEE802.11(b). For higher data rates (such as those illustrated in tables 6,8 and 10), the channel encoder may use the same convolution encoding asdescribed above or it may use a more powerful code, including aconvolutional code with more states, any one or more of the varioustypes of error correction codes (ECCs) mentioned above (e.g., RS, LDPC,turbo, TTCM, etc.) a parallel concatenated (turbo) code and/or a lowdensity parity check (LDPC) block code. Further, any one of these codesmay be combined with an outer Reed Solomon code. Based on a balancing ofperformance, backward compatibility and low latency, one or more ofthese codes may be optimal. Note that the concatenated turbo encodingand low density parity check will be described in greater detail withreference to subsequent Figures.

The interleaver 176 receives the encoded data and spreads it overmultiple symbols and transmit streams. This allows improved detectionand error correction capabilities at the receiver. In one embodiment,the interleaver 176 will follow the IEEE 802.11(a) or (g) standard inthe backward compatible modes. For higher performance modes (e.g., suchas those illustrated in tables 6, 8 and 10), the interleaver willinterleave data over multiple transmit streams. The demultiplexer 170converts the serial interleave stream from interleaver 176 intoM-parallel streams for transmission.

Each symbol mapper 180-184 receives a corresponding one of theM-parallel paths of data from the demultiplexer. Each symbol mapper180-182 lock maps bit streams to quadrature amplitude modulated QAMsymbols (e.g., BPSK, QPSK, 16 QAM, 64 QAM, 256 QAM, et cetera) accordingto the rate tables (e.g., tables 1-12). For IEEE 802.11(a) backwardcompatibility, double Gray coding may be used.

The map symbols produced by each of the symbol mappers 180-184 areprovided to the IFFT/cyclic prefix addition modules 186-190, whichperforms frequency domain to time domain conversions and adds a prefix,which allows removal of inter-symbol interference at the receiver. Notethat the length of the IFFT and cyclic prefix are defined in the modetables of tables 1-12. In general, a 64-point IFFT will be used for 20MHz channels and 128-point IFFT will be used for 40 MHz channels.

The space/time encoder 192 receives the M-parallel paths of time domainsymbols and converts them into P-output symbols. In one embodiment, thenumber of M-input paths will equal the number of P-output paths. Inanother embodiment, the number of output paths P will equal 2M paths.For each of the paths, the space/time encoder multiples the inputsymbols with an encoding matrix that has the form of

$\quad{\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \ldots & C_{{2M} - 1} & C_{2M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \ldots & {- C_{2M}^{*}} & {C_{{2M} - 1}\;}\end{bmatrix}.}$

The rows of the encoding matrix correspond to the number of input pathsand the columns correspond to the number of output paths.

FIG. 10B illustrates the radio portion of the transmitter that includesa plurality of digital filter/up-sampling modules 194-198,digital-to-analog conversion modules 200-204, analog filters 206-216,I/Q modulators 218-222, RF amplifiers 224-228, RF filters 230-234 andantennae 236-240. The P-outputs from the space/time encoder 192 arereceived by respective digital filtering/up-sampling modules 194-198. Inone embodiment, the digital filters/up sampling modules 194-198 are partof the digital baseband processing module and the remaining componentscomprise the plurality of RF front-ends. In such an embodiment, thedigital baseband processing module and the RF front end comprise adirect conversion module.

In operation, the number of radio paths that are active correspond tothe number of P-outputs. For example, if only one P-output path isgenerated, only one of the radio transmitter paths will be active. Asone of average skill in the art will appreciate, the number of outputpaths may range from one to any desired number.

The digital filtering/up-sampling modules 194-198 filter thecorresponding symbols and adjust the sampling rates to correspond withthe desired sampling rates of the digital-to-analog conversion modules200-204. The digital-to-analog conversion modules 200-204 convert thedigital filtered and up-sampled signals into corresponding in-phase andquadrature analog signals. The analog filters 206-214 filter thecorresponding in-phase and/or quadrature components of the analogsignals, and provide the filtered signals to the corresponding I/Qmodulators 218-222. The I/Q modulators 218-222 based on a localoscillation, which is produced by a local oscillator 100, up-convertsthe I/Q signals into radio frequency signals.

The RF amplifiers 224-228 amplify the RF signals which are thensubsequently filtered via RF filters 230-234 before being transmittedvia antennae 236-240.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver (as shown by reference numeral 250). These diagrams illustratea schematic block diagram of another embodiment of a receiver. FIG. 11Aillustrates the analog portion of the receiver which includes aplurality of receiver paths. Each receiver path includes an antenna, RFfilters 252-256, low noise amplifiers 258-262, I/Q demodulators 264-268,analog filters 270-280, analog-to-digital converters 282-286 and digitalfilters and down-sampling modules 288-290.

In operation, the antennae receive inbound RF signals, which areband-pass filtered via the RF filters 252-256. The corresponding lownoise amplifiers 258-262 amplify the filtered signals and provide themto the corresponding I/Q demodulators 264-268. The I/Q demodulators264-268, based on a local oscillation, which is produced by localoscillator 100, down-converts the RF signals into baseband in-phase andquadrature analog signals.

The corresponding analog filters 270-280 filter the in-phase andquadrature analog components, respectively. The analog-to-digitalconverters 282-286 convert the in-phase and quadrature analog signalsinto a digital signal. The digital filtering and down-sampling modules288-290 filter the digital signals and adjust the sampling rate tocorrespond to the rate of the baseband processing, which will bedescribed in FIG. 11B.

FIG. 11B illustrates the baseband processing of a receiver. The basebandprocessing includes a space/time decoder 294, a plurality of fastFourier transform (FFT)/cyclic prefix removal modules 296-300, aplurality of symbol demapping modules 302-306, a multiplexer 308, adeinterleaver 310, a channel decoder 312, and a descramble module 314.The baseband processing module may further include a mode managingmodule 175, which produces rate selections 171 and settings 179 based onmode selections 173. The space/time decoding module 294, which performsthe inverse function of space/time encoder 192, receives P-inputs fromthe receiver paths and produce M-output paths. The M-output paths areprocessed via the FFT/cyclic prefix removal modules 296-300 whichperform the inverse function of the IFFT/cyclic prefix addition modules186-190 to produce frequency domain symbols.

The symbol demapping modules 302-306 convert the frequency domainsymbols into data utilizing an inverse process of the symbol mappers180-184. The multiplexer 308 combines the demapped symbol streams into asingle path.

The deinterleaver 310 deinterleaves the single path utilizing an inversefunction of the function performed by interleaver 176. The deinterleaveddata is then provided to the channel decoder 312 which performs theinverse function of channel encoder 174. The descrambler 314 receivesthe decoded data and performs the inverse function of scrambler 172 toproduce the inbound data 98.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention. The AP point 1200 may compatible with any number ofcommunication protocols and/or standards, e.g., IEEE 802.11(a), IEEE802.11(b), IEEE 802.11(g), IEEE 802.11(n), as well as in accordance withvarious aspects of invention. According to certain aspects of thepresent invention, the AP supports backwards compatibility with priorversions of the IEEE 802.11x standards as well. According to otheraspects of the present invention, the AP 1200 supports communicationswith the WLAN devices 1202, 1204, and 1206 with channel bandwidths, MIMOdimensions, and at data throughput rates unsupported by the prior IEEE802.11x operating standards. For example, the access point 1200 and WLANdevices 1202, 1204, and 1206 may support channel bandwidths from thoseof prior version devices and from 40 MHz to 1.28 GHz and above. Theaccess point 1200 and WLAN devices 1202, 1204, and 1206 support MIMOdimensions to 4×4 and greater. With these characteristics, the accesspoint 1200 and WLAN devices 1202, 1204, and 1206 may support datathroughput rates to 1 GHz and above.

The AP 1200 supports simultaneous communications with more than one ofthe WLAN devices 1202, 1204, and 1206. Simultaneous communications maybe serviced via OFDM tone allocations (e.g., certain number of OFDMtones in a given cluster), MIMO dimension multiplexing, or via othertechniques. With some simultaneous communications, the AP 1200 mayallocate one or more of the multiple antennae thereof respectively tosupport communication with each WLAN device 1202, 1204, and 1206, forexample.

Further, the AP 1200 and WLAN devices 1202, 1204, and 1206 are backwardscompatible with the IEEE 802.11(a), (b), (g), and (n) operatingstandards. In supporting such backwards compatibility, these devicessupport signal formats and structures that are consistent with theseprior operating standards.

Generally, communications as described herein may be targeted forreception by a single receiver or for multiple individual receivers(e.g. via multi-user multiple input multiple output (MU-MIMO), and/orOFDMA transmissions, which are different than single transmissions witha multi-receiver address). For example, a single OFDMA transmission usesdifferent tones or sets of tones (e.g., clusters or channels) to senddistinct sets of information, each set of information transmitted to oneor more receivers simultaneously in the time domain. Again, an OFDMAtransmission sent to one user is equivalent to an OFDM transmission. Asingle MU-MIMO transmission may include spatially-diverse signals over acommon set of tones, each containing distinct information and eachtransmitted to one or more distinct receivers. Some single transmissionsmay be a combination of OFDMA and MU-MIMO. MIMO transceivers illustratedmay include SISO, SIMO, and MISO transceivers. The clusters employed forsuch communications may be continuous (e.g., adjacent to one another) ordiscontinuous (e.g., separated by a guard interval of band gap).Transmissions on different OFDMA clusters may be simultaneous ornon-simultaneous. Such wireless communication devices as describedherein may be capable of supporting communications via a single clusteror any combination thereof. Legacy users and new version users (e.g.,TGac MU-MIMO, OFDMA, MU-MIMO/OFDMA, etc.) may share bandwidth at a giventime or they can be scheduled at different times for certainembodiments.

FIG. 13 is a diagram illustrating an embodiment of a wirelesscommunication device, and clusters, as may be employed for supportingcommunications with at least one additional wireless communicationdevice. Generally speaking, a cluster may be viewed as a depiction ofthe mapping of tones, such as for an OFDM symbol, within or among one ormore channels (e.g., sub-divided portions of the spectrum) that may besituated in one or more bands (e.g., portions of the spectrum separatedby relatively larger amounts). As an example, various channels of 20 MHzmay be situated within or centered around a 5 GHz band. The channelswithin any such band may be continuous (e.g., adjacent to one another)or discontinuous (e.g., separated by some guard interval or band gap).Oftentimes, one or more channels may be situated within a given band,and different bands need not necessarily have a same number of channelstherein. Again, a cluster may generally be understood as any combinationone or more channels among one or more bands. As may be seen in thediagram, any respective cluster may be associated with any one or moreantennae (including as few as one antenna as well as up to all of theantennae) of the wireless communication device.

The wireless communication device of this diagram may be of any of thevarious types and/or equivalents described herein (e.g., AP, WLANdevice, or other wireless communication device including, though notlimited to, any of those depicted in FIG. 1, etc.). The wirelesscommunication device includes multiple antennae from which one or moresignals may be transmitted to one or more receiving wirelesscommunication devices and/or received from one or more other wirelesscommunication devices.

Such clusters may be used for transmissions of signals via various oneor more selected antennae. For example, different clusters are shown asbeing used to transmit signals respectively using different one or moreantennae.

FIG. 14 is a diagram illustrating an embodiment of a frame format thatmay be used in conjunction with a wireless communication device such asa WLAN device. Packet construction in accordance with the variousprinciples presented herein, generally speaking, may include a preamble,a signal field, and a payload. Again, generally, the preamble is usedfor carrier acquisition, synchronization, channel estimation, etc. Thesignal field is used to communicate frame specific parameters (e.g.,coding rate, frame length, etc.) to a receiving device. The payload isthe data portion of the packet.

A frame format may be modified based on a number of parameters,including, dependence upon the presence of other wireless communicationdevices in a communication system. In some instances, a communicationmay include various types of wireless communication devices havingdifferent respective capability sets (e.g., legacy devices, newerdevices, mixed mode devices, etc.).

For example, with some embodiments, in the 5 GHz spectrum, legacydevices may include those being compliant in accordance with IEEE802.11(a) and IEEE 802.11(n). Legacy devices must be able to recognizethat a packet has been transmitted and remain off the air for theduration of the packet (i.e., not transmit energy into the communicationchannel or communication medium in order to give access to othercommunication devices). Thus, packets formed in accordance with thevarious aspects presented herein may include certain portions thereinthat are compliant with legacy or prior standards, recommendedpractices, etc. As one example, a new packet may include a legacypreamble and a signal field along with a new, modified version of apayload. With such a novel packet structure, a legacy device will stillbe able to recognize the legacy preamble and decode the legacy signalfield. The legacy signal field contains information that tells thelegacy devices how long the packet will be on the air (i.e., occupy orbe using the communication channel or communication medium). The legacysignal field does not contain IEEE 802.11ac specific parameters (theseare contained in the IEEE 802.11ac signal field).

A packet having a particular type of frame format, such as a Greenfieldpacket that does not include certain portions therein that are compliantwith legacy or prior standards, recommended practices, etc. (i.e., nonlegacy supporting), may be used when only new version devices arepresent (e.g., no legacy or prior devices having compatibility withprevious standards and/or recommended practices). Such a packetstructure (Greenfield) need not include a legacy compatible preamble ora legacy compatible signal field, since no such devices are present. TheGreenfield packet may have a shorter preamble and a signal field thatyields a higher throughput.

Referring particularly to FIG. 14, various packet structures areillustrated as being compliant with various IEEE 802.11x standards(e.g., where x is a, n, ac, respectively). An IEEE 802.11a packet isshown including a legacy short training field (L-STF), a legacy longtraining field (L-LTF), a legacy signal field (L-SIG), followed by adata field.

An IEEE 802.11n mixed mode packet is shown including a legacy shorttraining field (L-STF), a legacy long training field (L-LTF), a legacysignal field (L-SIG), a high throughput signal field (HT-SIG), multiplehigh throughput long training fields (HT-LTF), followed by a data field.

An IEEE 802.11ac mixed mode packet is shown including a legacy shorttraining field (L-STF), a legacy long training field (L-LTF), a legacysignal field (L-SIG), a high throughput signal field (HT-SIG), a veryhigh throughput signal field (VHT-SIG), a very high throughput shorttraining field (VHT-STF), a very high throughput long training field(VHT-LTF), followed by a data field.

As may be seen when comparing the various types of packets, the IEEE802.11ac mixed mode packet does have some similarity with respect to theIEEE 802.11n mixed mode packet, as shown by a legacy portion (e.g.,similar to the IEEE 802.11n mixed mode packet and having some similarityto the IEEE 802.11a packet) and an IEEE 802.11ac portion including thevery high throughput portions.

The IEEE 802.11ac packet includes the IEEE 802.11a preamble and signalfield for detection by devices compliant with and operable with IEEE802.11a. Such a packet may have set a fixed rate of information of 6Mbps and a corresponding length based on its respective time on the air(i.e., time being transmitted via the communication channel orcommunication medium). The IEEE 802.11ac mixed mode packet is limited tothe time on the air (channel/medium) corresponding to the maximum sizeof an IEEE 802.11a packet.

The IEEE 802.11ac mixed mode packet includes the IEEE 802.11n preambleand signal field for detection by devices compliant with and operablewith IEEE 802.11n. When using the structure that is compatible withdevices compliant with and operable with IEEE 802.11n, the rate is setto modulation code set (MCS) 0, regular Guard Interval (GI), no spacetime block coding (STBC), and a corresponding length based on time onair (channel/medium).

As will be seen in various embodiments, the HT-SIG field need not beemployed in all embodiments (e.g., several embodiments do not use such aHT-SIG field). When an HT-SIG field is employed in a particularembodiment, it may be necessary for such a HT-SIG cyclic redundancycheck (CRC) to be valid so that HT device accepts the signal field anddefers the medium (i.e., does not occupy the channel/air). In the bottomembodiment of this diagram, the structure includes the VHT-SIG fieldshown as being immediately after such a HT-SIG field. The VHT-SIG fieldis 90 degrees rotated with respect to HT-STF field to allow for betterdiscrimination between the two respective fields. Other rotations (e.g.,besides only 90 degrees) are alternatively and also possible to assistin such discrimination as preferred in other embodiments. As such, theprobability of considering the HT-SIG field (when employed in a givenembodiment) and thereby treating a VHT mixed mode frame as in fact beinga valid HT frame should be relatively small. This problem typicallyoccurs when an HT device finds its MAC address and the frame checksequence (FCS) passes in its decoding of an IEEE 802.11ac mixed modeframe. The VHT short training field (VHT-STF), VHT long training field(VHT-LTF), and payload data portion all follow VHT-SIG field in the802.11ac mixed mode packet.

With respect to a signal field (SIG) as employed within such multi-userpackets as described herein, or variants thereof, the SIG field may bedistributed or partitioned into at least two separate signal fields(e.g., SIG A and SIG B) that are located in different portions of themulti-user packet. In certain embodiments, a first SIG field (e.g., SIGA) may be implemented in a portion of a multi-user packet thatcorresponds to a first operational mode (e.g., a legacy operationalmode), and a second SIG field (e.g., SIG B) may be implemented in aportion of a multi-user packet that corresponds to a second operationalmode (e.g., an IEEE 802.11ac (VHT) operational mode).

It is noted, that while the terminology of a multi-user packet is usedin various embodiments herein and in accordance with various aspects ofthe invention, such a packet may also support single user (SU) operation(e.g., such as in accordance with single user multiple input multipleoutput (SU-MIMO) in certain embodiments. The terminology of multi-userpacket is nonetheless employed herein because such a format of a packetcan be simultaneously compliant with and adapted to both single user(SU) and multi-user (MU) operation (e.g., multi-user multiple inputmultiple output (MU-MIMO), orthogonal frequency division multiple access(OFDMA), or combination OFDMA/MU-MIMO).

A first of the SIG fields includes information that may be processed anddecoded by all wireless communication devices within a communicationsystem, and a second of the SIG fields includes information that isspecific to one or more particular wireless communication devices withinthe communication system (e.g., pertaining to a specific once or morewireless communication devices, such as a specific, individual wirelesscommunication device or a specific subset or group of the wirelesscommunication devices within the communication system).

With respect to a given packet, certain of the wireless communicationdevices may receive, process and decode the first of the SIG fields(e.g., SIG A) and the second of the SIG fields (e.g., SIG B) within adistributed SIG field, while other of the wireless communication devicesmay only receive the first of the SIG fields (e.g., SIG A) (e.g., suchas if any precoding (steering) multi-user (MU) weights do not correspondto those respective wireless communication devices). For example, legacywireless communication devices (i.e., devices that are compliant with anolder version of a wireless communication standard) having such acapability would then not process and decode both the first of the SIGfields (e.g., SIG A) and the second of the SIG fields (e.g., SIG B)within a distributed SIG field. Generally speaking, multiple or all ofthe receiving wireless communication devices are typically operative toprocess and decode a first component of the distributed SIG field (e.g.,SIG A), and those wireless communication devices for which the secondportion is intended (e.g., those for which the precoding (steering)multi-user (MU) weights correspond) would then be operative to receive,process and decode both the first of the SIG fields (e.g., SIG A) andthe second of the SIG fields (e.g., SIG B) within a distributed SIGfield.

Again, it is a noted that while the first component of the distributedSIG field (e.g., SIG A) may be able to be processed and decoded by mostor all of the receiving wireless communication devices, all of thosereceiving wireless communication devices may not necessarily use any orall of the information therein (e.g., such a receiving wirelesscommunication device may operate by discarding all of part of themulti-user packet).

With respect to the locations of such a first component of thedistributed SIG field (e.g., SIG A) and as second component of thedistributed SIG field (e.g., SIG A), a designer is given wide latituderegarding their respective locations within such a multi-user packet.The precise locations of the at least first and second SIG fields withina multi-user packet may be varied. For example, particular where a firstSIG field (e.g., SIG A) and a second SIG field (e.g., SIG B) are locatedmay vary per application, by design or implementation choice, etc. Forexample, in some embodiments, the second component of the distributedSIG field (e.g., SIG B, including user-specific information) is locatedbefore a data field in the multi-user packet and at least one additionalfield is located between the second component of the distributed SIGfield (e.g., SIG B) and the data field (e.g., in which one or moreVHT-LTFs are located in between the second component of the distributedSIG field (e.g., SIG B) and the data field). In another embodiment, thesecond component of the distributed SIG field (e.g., SIG B, includinguser-specific information) is located adjacent to and preceding a datafield in the multi-user packet.

Also, within certain embodiments, the manner in which the variouscomponents of the distributed SIG field may be transmitted from awireless communication device differently. For example, a firstcomponent of the distributed SIG field (e.g., SIG A) may be transmittedomni-directionally from a transmitting wireless communication device,while a second component of the distributed SIG field (e.g., SIG B) maybe transmitted from a transmitting wireless communication device inaccordance with pre-coding or beamforming. In other words, the manner oftransmission may be modified as a function of various components withina multi-user packet (e.g., a first portion transmitted in accordancewith a first manner, and a second portion transmitted in accordance witha second manner). Such variable transmission functionality (e.g., SIG Aomni-directionally and SIG B in accordance with pre-coding orbeamforming) may be operative to ensure that all of the receivingwireless communication devices are able to receive and process a firstportion of the distributed SIG field that includes information that maybe used by multiple of the wireless communication devices (e.g., SIG A),while a second portion of the distributed SIG field (e.g., SIG B) istargeted for and processed only by those wireless communication devicesfor which the second portion of the distributed SIG field (e.g., SIG B)is intended. In one embodiment, such pre-coding or beamforming as may beperformed for the second portion of the distributed SIG field (e.g., SIGB) may be in accordance with space division multiple access (SDMA)signaling; such SDMA may be targeted to one or more of the receivingwireless communication devices.

Different formats of such multi-user packet may be employed toeffectuate the respective and different operational modes of single user(SU), multi-user (MU) resolvable LTFs, and MU non-resolvable LTFsoperational modes. For example, the preamble structure may vary for eachof these various operational modes (the SU, MU resolvable LTFs, and MUnon-resolvable LTFs operational modes). In some instances, havingdifferent frame formats for each respective operational mode may yield amore efficient (e.g., shorter) preamble structure for some of the cases.However, for other of the cases, there may be an increase in complexity(e.g., VHT devices oftentimes need to handle multiple frame formats, andwould then need to accommodate the multiple frame formats beingemployed). To ensure a more simplistic and less complex approach, acommon or same frame format may be employed in some embodiments. Whenemploying different types of frame formats, indicating which preamble isbeing used in a particular instance may be signaled in one of the fieldsof the multi-user packet (e.g., in the first component of thedistributed SIG field, VHT-SIG-A field using one or more of thefollowing (or equivalent) bits: MU-MIMO bit, and VHT-LTF Mode bit.

In some embodiments, a HT-SIG field may be inserted after the L-SIGfield for proper deferral of HT devices (e.g., IEEE 802.11n devices). Inalternative embodiments, the first component of the distributed SIGfield (e.g., VHT-SIG-A) may be replaced by HT-SIG for proper deferral ofHT devices (e.g., IEEE 802.11n devices).

When operating in accordance with SU-MIMO, beamforming and precoding(steering) may also be employed when transmitted such multi-user packets(e.g., such as in accordance with certain portions of the IEEE 802.11nspecification). It is noted that, when operating in accordance withSU-MIMO, the first of the SIG fields (e.g., SIG A) may include all ofthe necessary information for processing and decoding at least one fieldwithin the multi-user packet (e.g., the second of the SIG fields (e.g.,SIG B) may include no such relevant and useful information therein foruse in processing and decoding at least one field within the multi-userpacket).

FIG. 15 is a diagram illustrating an embodiment of possible frameformats, corresponding to single user multiple input multiple output(SU-MIMO), that may be used in conjunction with a wireless communicationdevice such as a WLAN device. This diagram shows three possiblearrangements of the respective fields within a frame that may be used inaccordance with SU-MIMO operations.

FIG. 16 is a diagram illustrating an embodiment of a possible frameformat, corresponding to multi-user multiple input multiple output(MU-MIMO) and particularly in accordance with a resolvable operationalmode (e.g., resolvable VHT-LTFs mode), that may be used in conjunctionwith a wireless communication device such as a WLAN device. This diagramshows a possible arrangements of the respective fields within a framethat may be used in accordance with MU-MIMO operations when operating inaccordance with a resolvable operational mode (e.g., a resolvable LTFsoperational mode) in which the communication channel corresponding toeach respective wireless communication device may include precoding(steering) weights which may be estimated at each wireless communicationdevice (e.g., each respective wireless communication device may obtainadditional information about other wireless communication devicespresent in the same MU frame; such additional information may correspondto other user's precoding (steering) weights that may be present withinthe same MU frame). Such additional information about other wirelesscommunication devices present in the same MU frame (e.g., other user'sprecoding (steering) weights) may be employed for performinginterference cancellation and/or suppression based on interference suchas may be caused by one or more of the other wireless communicationdevices within the communication system.

Moreover, it is noted that, when operating in accordance with such aresolvable operational mode (e.g., a resolvable LTFs operational mode),a modified or slightly longer preamble may be desirable in that aslightly greater number of LTFs may be required.

FIG. 17 is a diagram illustrating an embodiment of possible frameformats, corresponding to multi-user multiple input multiple output(MU-MIMO) and particularly in accordance with a non-resolvableoperational mode (e.g., non-resolvable VHT-LTFs mode), that may be usedin conjunction with a wireless communication device such as a WLANdevice. This diagram shows two possible arrangements of the respectivefields within a frame that may be used in accordance with MU-MIMOoperations when operating in accordance with a non-resolvableoperational mode (e.g., a non-resolvable LTFs operational mode) in whicheach respective wireless communication device is operative to estimateonly the intended communication channel (e.g., corresponding to thatparticular wireless communication device), and may also includeemploying precoding (steering) weights to all or specific portions ofthe multi-user packet. It is noted that, when operating in accordancewith such a non-resolvable operational mode (e.g., a non-resolvable LTFsoperational mode), a relatively shorter preamble may be employed havinga fewer number of LTFs than may be required when operating in accordancewith a resolvable operational mode (e.g., a resolvable LTFs operationalmode).

As mentioned elsewhere herein, the respective components of adistributed SIG field (e.g., SIG A and SIG B) may be located differentlywithin different embodiments. Some embodiments place the secondcomponent of the distributed SIG field (e.g., SIG B) is located before adata field in the multi-user packet and at least one additional field islocated between the second component of the distributed SIG field (e.g.,SIG B) and the data field (e.g., in which one or more VHT-LTFs arelocated in between the second component of the distributed SIG field(e.g., SIG B) and the data field). In other embodiments, the secondcomponent of the distributed SIG field (e.g., SIG B, includinguser-specific information) is located adjacent to and preceding a datafield in the multi-user packet.

FIG. 18A and FIG. 18B are diagrams illustrating embodiments of a frameformat, showing a distributed SIG field, that may be used in conjunctionwith a wireless communication device such as a WLAN device.

As can be seen with respect to each of the possible options for each ofthe SU, MU Resolvable LTFs, and MU Non-Resolvable LTFs preamble, thereis one frame format that is common among each operational mode (e.g., asshown in FIG. 18B); this common frame format may be selected and beemployed for supporting each of the respective operational modes. Assuch, all of the wireless communication devices may be implemented toaccommodate this common frame format to ensure that a relatively lowercomplexity may be achieved for those wireless communication devices inwhich it is desired to support multiple operational modes.

Again, it is noted that a particular preamble structure may be selectedsuch that the structure is similar or the same for all cases in order toprovide a lower implementation complexity, while considering that somepreambles in this vein may be less efficient (e.g., longer).Alternatively, a particular preamble structure may be selected such thatthe structure is different for some or all of the cases, whileconsidering that such implementations may provide for a higherimplementation complexity yet allow for the use of more efficientpreambles (e.g., shorter).

Selecting operation in accordance with a single MU preamble (e.g., suchas within FIG. 18B may be beneficial in a preferred embodiment byproviding for the reduced complexity among the various wirelesscommunication devices within the communication system. As can be seenwhen selecting such a common format for the multi-user packet (e.g.,FIG. 18B), such a frame format allows for operation in accordance witheither the MU resolvable LTFs operational mode or the MU non-resolvableLTFs operational mode. In some instances, the VHT-LTF mode bit may notbe required.

The frame format as depicted in FIG. 18B is an embodiment of a unifiedSU/MU-MIMO 802.11ac legacy mixed mode packet structure. Such a singlemulti-user packet structure is operative to support each of the variousoperational modes: single user (SU) as well the two operational modes ofmulti user (MU) resolvable operational mode (e.g., a resolvable LTFsoperational mode) and a non-resolvable operational mode (e.g., anon-resolvable LTFs operational mode). Selecting one multi-user packetstructure allows for a simpler solution and less complexity than tryingto implement different and respective types of multi-user packetstructures for the different, respective operational modes.

Again, the packet (preamble) structure of the multi-user packet in FIG.18B is operative to support the two MU operational modes. If desired,the mode type may be indicated in the first component of the distributedSIG field (e.g., VHT-SIG-A, using a single bit, such as in accordancewith “VHT-LTF Mode” indication). Again, these two MU operational modesmay be the MU resolvable LTFs operational mode and the MU non-resolvableLTFs operational mode. The MU resolvable LTFs operational mode mayoperate such that each respective wireless communication device eachrespective wireless communication device may obtain additionalinformation about other of the wireless communication devices present inthe same MU frame (e.g., other user's precoding (steering) weights thatmay be present within the same MU frame), which may result in a longerpreamble (e.g., a greater number of VHT-LTFs may be required).

The MU non-resolvable LTFs operational mode may operate in accordancewith each respective wireless communication device performing channelestimation of only the intended respective communication channel (e.g.,corresponding to that particular wireless communication device). The MUnon-resolvable LTFs operational mode may include some precoding(steering) weights as well, and can provide for a shorter preamblelength than as required in accordance with the MU resolvable LTFsoperational mode.

In accordance with both of these modes (e.g., MU resolvable LTFsoperational mode and MU non-resolvable LTFs operational mode), bothoperational modes have common portion (e.g., VHT-SIG-A) and a userspecific portion of the distributed SIG field (e.g., VHT-SIG-B). Somebits in the VHT-SIGs may be relevant to one of the operational modes,but not to another mode. As such, certain bits may be ignored orinterpreted differently for the different respective operational modes.

Operation in accordance with a SU-MIMO operational mode (which mayinclude beamforming or precoding (steering) weights may be indicated inthe VHT-SIG-A field. In one embodiment, the SU-MIMO case may beindicated in the VHT-SIG-A field by setting MU-MIMO bit to “0” (e.g.,“MU-MIMO” indication may be used (1 bit)), for example (or SU-MIMO bitset to “1”). In another embodiment, the SU-MIMO or MU-MIMO cases may beindicated using the GroupID field (e.g., “0” for “SU-MIMO” and non-zerofor MU-MIMO).

The HT-LTF Mode bit may be set to “0” or ignored. Also, when operatingin accordance with an embodiment such as within FIG. 18A, the firstVHT-LTF field may be used in combination with VHT-LTF fields after theVHT-SIG-B for estimating multiple channels, in order to save on thenumber of LTFs used.

Again, in some applications, a HT-SIG field may be inserted after theL-SIG for proper deferral of HT devices (e.g., IEEE 802.11n devices),and in other applications, a first field of the distributed SIG field(e.g., VHT-SIG-A) may be replaced by a HT-SIG for proper deferral of HTdevices (e.g., 802.11n devices).

FIG. 19 is a diagram illustrating an embodiment of a frame format,having a unified preamble as applicable for both SU and MU operationalmodes (including both a MU resolvable operational mode and a MUnon-resolvable operational mode) in which a common set of precoding(steering) weights being applied throughput a portion of the multi-userpacket for each user. Such precoding (steering) weights may begin at andinclude VHT-STF for both MU-MIMO and SU-MIMO embodiments. Also, eachrespective user/wireless communication device may have differentrespective precoding (steering) weights starting from and includingVHT-STF until the end of the packet.

Such a MU operational mode may be indicated in the VHT-SIG-A by settingMU-MIMO bit to “1”. For example, the VHT-LTF Mode bit may be set to “0”to indicate the non-resolvable LTFs operational mode. Each respectivewireless communication device may have a different respective number ofLTFs and therefore a different preamble length, depending on the numberof communication channels to be estimated.

Referring again to the multi-user packet structure of FIG. 18B (e.g.,also shown with respect to FIG. 19 that provides a common structureoperative for supporting each of the various operational modes: SUoperational mode, MU resolvable operational mode, and MU non-resolvableoperational mode), each respective SIG field (e.g., L-SIG, HT-SIG,VHT-SIG-A or VHT-SIG-B) may include one or more OFDM symbols, dependingon the amount of information that is to be included.

With respect to the legacy portion of the multi-user packet, legacy STF,LTF, and signal (SIG) field may be employed for detection by IEEE802.11a and IEEE 802.11n compliant and operable wireless communicationdevices. The information rate may be set to 6 Mbps, and thecorresponding multi-user packet length may be based on duration ofaccess to the medium (e.g., time on the air). The IEEE 802.11ac mixedmode multi-user packet may be limited to duration of access to themedium (e.g., time on the air) as being equal to a maximum size of anIEEE 802.11a packet. The first component of the distributed SIG field(e.g., common SIG field component, VHT-SIG-A) contains information thatmay be processed and decoded by all users and may be needed for some orall of the wireless communication devices for processing of the VHT-STFand VHT-LTF fields. Such information contained within the firstcomponent of the distributed SIG field (e.g., VHT-SIG-A) may bebandwidth, number of VHT long training fields, etc. Again, as mentionedelsewhere herein, the first component of the distributed SIG field(e.g., VHT-SIG-A) may be transmitted from a transmitting wirelesscommunication device omni-directionally (e.g., with no beamforming(precoding) or steering weights).

With respect to the VHT portion of the multi-user packet, the VHT-STFand VHT-LTF fields may be employed for automatic gain control (AGC) andchannel estimation, respectively. The second component of thedistributed SIG field (e.g., VHT-SIG-B) contains user specific signalfield information such as MCS, packet length (bytes), etc. Again, asalso mentioned elsewhere herein, the second component of the distributedSIG field (e.g., VHT-SIG-B) may be transmitted from a transmittingwireless communication device in accordance with beamforming (precoding)and steering weights when being transmitted to a single or multipleother wireless communication devices.

As may be seen, the SIG field may be partitioned into various componentsand distributed over different respective locations within the frame. Ina preferred embodiment, the first component of the distributed SIG field(e.g., VHT-SIG-B) is included in a legacy portion of the packet, and thesecond component of the distributed SIG field (e.g., VHT-SIG-B) isincluded in the VHT portion of the packet.

Various embodiments presented herein with respect to formats of some ofthe various fields within such packets (e.g., possible and variantformats of the first component of the distributed SIG field (e.g.,VHT-SIG-B), and the second component of the distributed SIG field (e.g.,VHT-SIG-B)), it is noted that such embodiments are exemplary, and agiven design or implementation has great latitude to select any desiredallocation of bits and individual fields therein as may be desired orappropriate for a given application.

FIG. 20 is a diagram illustrating an embodiment of a format of a firstSIG field (e.g., VHT-SIG-A) as may be employed in accordance with adistributed SIG field. This first SIG field (e.g., SIG A) containsinformation that may be processed and decoded by to all wirelesscommunication devices within the communication system, and may be usefulfor some or all of the those wireless communication devices. Thisparticular embodiment includes the following individual fields thereinwith the number of bits allocation for each field as shown in thediagram:

-   -   Bandwidth—up to 4 different packet bandwidths allowed (20, 40,        and 80 MHz expected, possibly 60 MHz)    -   N_LTF—number of VHT long training symbols        -   Assumed to be the same for all users        -   Any long training symbols beyond the number of space time            streams for a given user (signaled in VHT-SIG-B) may be used    -   Short_GI (SGI)—two different guard interval sizesCoding        type—allows for 2 different types of codes    -   Not sounding    -   Aggregation—signals whether or not the packet contains an A-MPDU    -   Reserved bits        -   Some of the reserved bits may be used for MCS and/or Length            fields (better protected (CRC) than similar information in            L-SIG)        -   Some of the reserved bits may be used for MCS for receiving            users in serial (sequence)        -   Some of the Length field bits in VHT-SIG-B may be moved to            VHT-SIG-A        -   Some of the reserved bits may be used for MU and/or MU-MIMO            indication    -   CRC—cyclic redundancy check to validate other fields of        VHT-SIG-A    -   Tail bits—termination pattern for convolutional code

Again, it is noted that the particular order of the individual fieldswithin VHT-SIG-A may change as desired in a particular application.Certain embodiments may always include the last two fields as being CRCand Tail Bits. Also, the bit widths of fields may be changed asnecessary. Also, other fields may be added, and any of above fields maybe transmitted in the second SIG field (e.g., SIG B) instead of or inaddition to the first SIG field (e.g., SIG A), certain fields and/orbits may be removed entirely from the components of the distributed SIGfield, or they may be ordered differently.

FIG. 21 is a diagram illustrating an embodiment of constellations as maybe employed for at least two orthogonal frequency division multiplexing(OFDM) symbols that may be employed in accordance with a first SIG field(e.g., VHT-SIG-A) as may be employed in accordance with a distributedSIG field. These two symbols are sent as 6 Mbps within an IEEE 802.11aframe replicated in each 20 MHz bandwidth portion (e.g., within each 20MHz cluster). These symbols include 48 information bits

The first OFDM symbol may be sent with +/−1 binary phase shift keying(BPSK) modulation. In accordance with such operation, those wirelesscommunication devices operating in accordance with IEEE 802.11 can bespoofed into classifying the frame as an IEEE 802.11a frame.

The second OFDM symbol may be sent with +/−j BPSK modulation, andreceiving wireless communication devices may then be allowed to classifythe frame as a VHT packet.

FIG. 22 is a diagram illustrating an embodiment of a format of a secondSIG field (e.g., VHT-SIG-B) as may be employed in accordance with adistributed SIG field. Again, the second SIG field (e.g., VHT-SIG-B)includes information that is specific to a single packet and/or one ormore wireless communication devices. This particular embodiment includesthe following individual fields therein with the number of bitsallocation for each field as shown in the diagram:

-   -   MCS—modulation and coding scheme used on data—may be 7 or 8 bits    -   Length—number of payload bytes in packet—may be 18 to 24 bits    -   STBC—mode of space time block coding used on data    -   Smoothing—denotes smoothing of channel estimate is recommended    -   Reserved bits    -   CRC—cyclic redundancy check to validate other fields of        VHT-SIG-B    -   Tail bits—termination pattern for convolutional code

As analogously mentioned above with respect to one possible variant ofthe first SIG field (e.g., SIG A) of a distributed SIG field, the orderof the fields within the second SIG field (e.g., SIG B) of a distributedSIG field may change.

Certain embodiments may always include the last two fields as being CRCand Tail Bits. Also, the bit widths of fields may be changed asnecessary. Also, other fields may be added, and any of above fields maybe transmitted in the first SIG field (e.g., SIG A) instead of or inaddition to the second SIG field (e.g., SIG B), certain fields and/orbits may be removed entirely from the components of the distributed SIGfield, or they may be ordered differently.

For example, an alternative embodiment for the VHT-SIG-B field contains48 information bits that may be transmitted as follows:

-   -   Sent using IEEE 802.11a tone mapping, replicated in each 20 MHz        channel in bandwidth    -   May be sent as 2 OFDM symbols using 6 Mbps IEEE 802.11a rate    -   May be sent as 1 OFDM symbol using 12 Mbps IEEE 802.11a rate    -   May also be sent as 1 OFDM symbol using 4 pulse amplitude        modulation (PAM) on each tone (also 12 Mbps)    -   BPSK, 4 PAM or QPSK constellations may be sent with 0 or 90        degree rotation on all symbols

It is noted that transmitting the various fields such as L-SIG, HT-SIGor VHT-SIG-A/B in accordance with 4-PAM or QPSK modulation caneffectuate a doubling of the number of coded bits transmitted within anOFDM symbol (as compared to BPSK). This could be used to transmitadditional SIG information without increasing the number of OFDMsymbols, or it could be used to reduce the number of OFDM symbols usedto transmit a fixed number of bits.

For better protection, additional coding may be employed with respect toinformation bits (e.g., the data portion(s)) within a multi-user packet.If desired, a relatively simple and easily implanted code could berepetition code (e.g., bits being repeated) to provide for some codinggain.

With respect to MAC protection, if the frames are beamformed from abeginning of the frame (e.g., for the SU or MU case), request to send(RTS) and clear to send (CTS) exchanges or clear to send to self(CTS2SELF) may be employed to protect the frame exchange. If VHTGreenfield (beamformed or omni-directional) is used, the RTS/CTS orCTS2SELF may be used to decrease in legacy or HT format may be used toprotect the frame exchange, or RTC/CTS or CTS2SELF in VHT format may beused to decrease the collision probability.

If VHT-HT mixed mode (beamformed or omni-directional) is used (e.g.,frames do not include L-SIG field), then RTC/CTS or CTS2SELF in legacyformat may be used to protect the frame exchange, or RTC/CTS or CTS2SELFin HT or VHT format may be used to decrease the collision probability.

If the frames include omni-directional length information, then RTS/CTSor CTS2SELF may be used to decrease the probability of collision.

FIG. 23 is a diagram illustrating an alternative embodiment of a formatof a first SIG field (e.g., VHT-SIG-A) as may be employed in accordancewith a distributed SIG field. This first SIG field (e.g., SIG A)contains information that may be processed and decoded by to allwireless communication devices within the communication system, and maybe useful for some or all of the those wireless communication devices.This particular embodiment includes the following individual fieldstherein with the number of bits allocation for each field as shown inthe diagram:

-   -   Length/Duration (12 bit)    -   Bandwidth (2 bits)    -   Coding Type (1 bit)    -   Not Sounding (1 bit)    -   SGI (1 bit)    -   MU-MIMO bits (15 bits)        -   MU-MIMO indication (1 bit)        -   VHT-LTF Mode (1 bit)        -   GroupID (4 bits)        -   AID list (9 bits)    -   CRC (8 bits)    -   BCC tail bits (6 bits)    -   Reserved bits

This diagram specifically corresponds to an instance for operating inaccordance with the MU resolvable operational mode (e.g., MU resolvableVHT-LTFs mode), which may be indicated by setting the LTF mode bit to“1”).

Alternatively, operation in accordance with the MU non-resolvableoperational mode (e.g., MU non-resolvable VHT-LTFs mode), which may beindicated by setting the LTF mode bit to “0”), and by also employing asimilar definition of bits with at least one exception being that theGroupID (4 bits) and some of the bits in the AID list (e.g., 6 bits outof 9 bits) are not relevant. Those bits can be defined differently whenLTF mode is set to 0 (e.g., when operating in accordance with the MUnon-resolvable operational mode (e.g., MU non-resolvable VHT-LTFsmode)).

Again, the order of the fields within the first SIG field (e.g., SIG A)of a distributed SIG field may change. Also, the bit widths of fieldsmay be changed as necessary. Also, other fields may be added, and any ofabove fields may be transmitted in the first SIG field (e.g., SIG A)instead of or in addition to the second SIG field (e.g., SIG B), certainfields and/or bits may be removed entirely from the components of thedistributed SIG field, or they may be ordered differently.

FIG. 24 is a diagram illustrating an alternative embodiment of a formatof a second SIG field (e.g., VHT-SIG-B) as may be employed in accordancewith a distributed SIG field.

This particular embodiment includes the following individual fieldstherein with the number of bits allocation for each field as shown inthe diagram:

-   -   MCS—modulation and coding scheme used on data—may be 7 or 8 bits    -   STBC—mode of space time block coding used on data—may be 2 or 3        bits    -   Smoothing—denotes smoothing of channel estimate is        recommended—may be 1 bit    -   CRC—cyclic redundancy check to validate other fields of        VHT-SIG-B—may be 4 or 8 bits    -   BCC Tail bits—termination pattern for convolutional code—may be        6 bits

Again, the order of the fields within the second SIG field (e.g., SIG B)of a distributed SIG field may change. Also, the bit widths of fieldsmay be changed as necessary. Also, other fields may be added, and any ofabove fields may be transmitted in the first SIG field (e.g., SIG A)instead of or in addition to the second SIG field (e.g., SIG B), certainfields and/or bits may be removed entirely from the components of thedistributed SIG field, or they may be ordered differently.

FIG. 25A, FIG. 25B, FIG. 26A, FIG. 26B, FIG. 27A, and FIG. 27B arediagrams illustrating various embodiments of methods for operating oneor more wireless communication devices.

Referring to method 2500 of FIG. 25A, the method 2500 describesoperations as may be performed within a transmitting wirelesscommunication device. The method 2500 begins by generating a multi-userpacket including a distributed signal (SIG) field composed of at leasttwo SIG fields, as shown in a block 2510. Such generation of amulti-user packet may be performed in accordance with a basebandprocessing module (e.g., such as in accordance with the basebandprocessing module as described within FIG. 2) that is implemented withina wireless communication device.

The method 2500 continues by transmitting the multi-user packet to aplurality of wireless communication devices, as shown in a block 2520.The transmission of the multi-user packet may be transmitted using oneor more antennae of such a wireless communication device.

Such a multi-user packet that includes a first SIG field and a secondSIG field therein can include different types of information in each ofthe respective SIG fields. A first SIG field within the multi-userpacket may include first information employed by each of the pluralityof wireless communication devices for decoding at least one field withinthe multi-user packet, as shown in a block 2520 a. A second SIG fieldwithin the multi-user packet may include second information employed byat least one of the plurality of wireless communication devices fordecoding at least one field within the multi-user packet correspondingto the at least one of the plurality of wireless communication devices,as shown in a block 2520 b.

In some embodiments, the at least one field within the multi-user packetthat gets decoded based on the first information contained within thefirst SIG field is the very same field that gests decoded based on thesecond information contained within the second SIG field; in otherwords, in some instances, both the first information within the firstSIG field and the second information within the second SIG field areemployed for decoding at least one other field within the multi-userpacket (e.g., a data field within the multi-user packet). In such anembodiment, the at least one field within the multi-user packet isdecoded using both the first information and the second informationcontained within the first and second SIG fields, respectively.

Moreover, in some embodiments, the first information extracted from thefirst SIG field is employed for use in decoding the second SIG field toextract the second information there from. The first information mayalso be employed in decoding not only the second SIG field but alsoanother field within the multi-user packet (e.g., a data field withinthe multi-user packet). In some embodiments when the first SIG field isemployed for use in decoding the second SIG field to extract the secondinformation there from, this second information from the second SIGfield (e.g., that was extracted using the first information from thefirst SIG field) may be used in decoding another field within themulti-user packet (e.g., possibly also including the data field withinthe multi-user packet).

In even other embodiments, both the first information contained withinthe first SIG field and the second information contained within thesecond SIG field are extracted before decoding the at least one fieldwithin the multi-user packet. In such an embodiment, both the firstinformation contained within the first SIG field and the secondinformation contained within the second SIG field would be extractedbefore processing the at least one field within the multi-user packet.

Referring to method 2501 of FIG. 25B, the method 2501 describesoperations as may be performed within a transmitting wirelesscommunication device. This embodiment shows a variant of the priorembodiment specifically enumerating with specificity possible optionsfor contents of the certain of the fields therein. The method 2501begins by generating a multi-user packet including a distributed signal(SIG) field such that SIG A being included in a first operational modeportion (e.g., legacy portion) and SIG B being included in a secondoperational mode portion (e.g., IEEE 802.11ac (VHT) portion) of themulti-user packet, as shown in a block 2511. Such generation of amulti-user packet may be performed in accordance with a basebandprocessing module (e.g., such as in accordance with the basebandprocessing module as described within FIG. 2) that is implemented withina wireless communication device.

The method 2501 then operates by transmitting the multi-user packet to aplurality of wireless communication devices, as shown in a block 2521.The transmission of the multi-user packet may be transmitted using oneor more antennae of such a wireless communication device. The SIG Afield includes information employed by each of the plurality of wirelesscommunication devices for processing or decoding at least one fieldwithin the multi-user packet, as shown in a block 2521 a. In someinstances, the at least one field (e.g., being two fields in this case)that gets decoded using information included within the SIG A field areboth the VHT-STF and VHT-LTF fields.

In this embodiment, the SIG B field includes information (e.g., MCS,packet length (bytes), etc.) employed by a specific one or more of theplurality of wireless communication devices for processing or decodingat least one field within the multi-user packet, as shown in a block2521 b. In some embodiments, information extracted from both the SIG Afield and the SIG B field are employed in decoding at least one fieldwithin the multi-user packet (e.g., information within both the SIG Afield and information within the SIG B field may be employed fordecoding at least one other field within the multi-user packet).

Alternatively, the information extracted from the SIG A field may beemployed for use in decoding the SIG B field to extract the secondinformation there from. In other words, information extracted from theSIG A field may be used to direct the decoding of the SIG B field toextract the information (e.g., MCS, packet length (bytes), etc.) thatmay be employed by a specific one or more of the plurality of wirelesscommunication devices for processing or decoding at least one fieldwithin the multi-user packet.

Referring to method 2600 of FIG. 26A, the method 2600 describesoperations as may be performed within a transmitting wirelesscommunication device. The method 2600 begins by generating a multi-userpacket including a distributed signal (SIG) field composed of at leasttwo SIG fields, such that a first SIG field being included in a firstoperational mode portion (e.g., legacy portion) and a second SIG fieldbeing included in a second operational mode portion (e.g., IEEE 802.11ac(VHT) portion) of the multi-user packet, as shown in a block 2610.Again, within this multi-user packet may be performed in accordance witha baseband processing module (e.g., such as in accordance with thebaseband processing module as described within FIG. 2) that isimplemented within a wireless communication device.

The method 2600 continues by transmitting the first operational modeportion (e.g., legacy portion, that includes the first SIG field) of themulti-user packet to a plurality of wireless communication devicesomni-directionally, as shown in a block 2620. The method 2600 thenoperates by transmitting the second operational mode portion (e.g., IEEE802.11ac (VHT) portion, that includes the second SIG field) of themulti-user packet to the plurality of wireless communication devices inaccordance with beamforming (steering) or precoding, as shown in a block2630. The transmission of the various portions of such a multi-userpacket may be transmitted using one or more antennae of such a wirelesscommunication device.

Referring to method 2601 of FIG. 26B, the method 2601 describesoperations as may be performed within a transmitting wirelesscommunication device. The 2601 begins by receiving a multi-user packetincluding a distributed signal (SIG) field composed of at least two SIGfields (e.g., at least a first SIG field and a second SIG field), asshown in a block 2611. The receipt of such a multi-user packet may beeffectuated using one or more antennae of such a wireless communicationdevice.

The method 2601 then operates by processing the first SIG field toextract information for use in processing a first at least one fieldwithin the multi-user packet, as shown in a block 2621. The method 2601continues by processing the first at least one field within themulti-user packet using the first information extracted from the firstSIG field, as shown in a block 2631. In some embodiments, theinformation extracted from the first SIG field corresponds toinformation employed for processing or decoding VHT-STF and VHT-LTFwithin the multi-user packet.

The method 2601 then operates by processing the second SIG field toextract second information for use in processing a second at least onefield within the multi-user packet, as shown in a block 2641. The method2601 continues by processing the second at least field within themulti-user packet using the second information extracted from the secondSIG field, as shown in a block 2651. In some embodiments, theinformation extracted from the second SIG field corresponds toinformation such as MCS, packet length (bytes), etc. employed forprocessing or decoding at least one portion of the multi-user packet.

Referring to method 2700 of FIG. 27A, the method 2700 describesoperations as may be performed within a transmitting wirelesscommunication device. The 2700 begins by receiving a multi-user packetincluding a distributed signal (SIG) field composed of at least two SIGfields (e.g., at least a first SIG field and a second SIG field), asshown in a block 2710. The method 2700 continues by processing the firstSIG field to first extract information for use in processing at leastone field within the multi-user packet, as shown in a block 2720. Themethod 2700 then operates by processing the second SIG field to secondextract information for use in processing the at least one field withinthe multi-user packet, as shown in a block 2730.

The method 2700 continues by processing the at least one field withinthe multi-user packet using the first information extracted from thefirst SIG field and the second extracted from the second SIG field, asshown in a block 2740. As can be seen, information extracted from boththe first SIG field and the second SIG field may be employed for use indecoding the at least one field within the multi-user packet.

As can be seen in this embodiment, information extracted from both thefirst SIG field and the second SIG field may be employed in processingand decoding at least one field within the multi-user packet (e.g.,information within both the first SIG field and information within thesecond SIG field may be employed for decoding at least one other fieldwithin the multi-user packet).

Referring to method 2701 of FIG. 27B, the method 2701 describesoperations as may be performed within a transmitting wirelesscommunication device. The 2701 begins by receiving a multi-user packetincluding a distributed signal (SIG) field composed of at least two SIGfields (e.g., at least a first SIG field and a second SIG field), asshown in a block 2711.

The method 2701 then operates by processing the first SIG field toextract first information for use in processing the second SIG field, asshown in a block 2721. The method 2701 continues by using the firstinformation extracted from the first SIG field for processing the secondSIG field to extract second information for use in processing at leastone field within the multi-user packet, as shown in a block 2731. As canbe seen, the first information extracted from the first SIG field may beemployed for use in and for directing the processing and decoding of thesecond SIG field to extract the second information there from.

The method 2701 then operates by processing the at least one fieldwithin the multi-user packet using the second information extracted fromthe second SIG field (and optionally also using the first informationextracted from the first SIG field), as shown in a block 2741.Optionally, in some embodiments, the method may also operate by usingthe first information extracted from the first SIG field in conjunctionwith the second information extracted from the second SIG field inprocessing the at least one field within the multi-user packet.

This embodiment described above shows an example where informationextracted from the first SIG field is employed to process and decode thesecond SIG field to extract second information from the second SIGfield. This second information may then be employed for processing anddecoding at least one field within the multi-user packet. In otherwords, information extracted from the first SIG field may be used todirect the decoding of the second SIG field to extract information thatmay be employed by one or more of the plurality of wirelesscommunication devices for processing or decoding at least one fieldwithin the multi-user packet. Of course, both the first information andthe second information may be employed to decode the at least one fieldwithin the multi-user packet.

It is noted that the various modules, circuitries, functional blocks,etc. (e.g., for encoding, for decoding, for baseband processing, etc.)described herein may be a single processing device or a plurality ofprocessing devices. Such a processing device may be a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The operational instructionsmay be stored in a memory. The memory may be a single memory device or aplurality of memory devices. Such a memory device may be a read-onlymemory (ROM), random access memory (RAM), volatile memory, non-volatilememory, static memory, dynamic memory, flash memory, and/or any devicethat stores digital information. It is also noted that when theprocessing module implements one or more of its functions via a statemachine, analog circuitry, digital circuitry, and/or logic circuitry,the memory storing the corresponding operational instructions isembedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry. In such anembodiment, a memory stores, and a processing module coupled theretoexecutes, operational instructions corresponding to at least some of thesteps and/or functions illustrated and/or described herein.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention.

One of average skill in the art will also recognize that the functionalbuilding blocks, and other illustrative blocks, modules and componentsherein, can be implemented as illustrated or by discrete components,application specific integrated circuits, processors executingappropriate software and the like or any combination thereof.

Moreover, although described in detail for purposes of clarity andunderstanding by way of the aforementioned embodiments, the presentinvention is not limited to such embodiments. It will be obvious to oneof average skill in the art that various changes and modifications maybe practiced within the spirit and scope of the invention, as limitedonly by the scope of the appended claims.

Mode Selection Tables:

TABLE 1 2.4 GHz, 20/22 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR Barker 1 BPSKBarker 2 QPSK 5.5 CCK 6 BPSK 0.5 1 48 24 −5 −82 16 32 9 BPSK 0.75 1 4836 −8 −81 15 31 11 CCK 12 QPSK 0.5 2 96 48 −10 −79 13 29 18 QPSK 0.75 296 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96 −16 −74 8 24 36 16-QAM 0.75 4192 144 −19 −70 4 20 48 64-QAM 0.666 6 288 192 −22 −66 0 16 54 64-QAM0.75 6 288 216 −25 −65 −1 15

TABLE 2 Channelization for Table 1 Frequency Channel (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 3 Power Spectral Density (PSD) Mask for Table 1 PSD Mask 1Frequency Offset dBr −9 MHz to 9 MHz 0 +/−11 MHz −20 +/−20 MHz −28 +/−30MHz and −50 greater

TABLE 4 5 GHz, 20 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR 6 BPSK 0.5 148 24 −5 −82 16 32 9 BPSK 0.75 1 48 36 −8 −81 15 31 12 QPSK 0.5 2 96 48−10 −79 13 29 18 QPSK 0.75 2 96 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96−16 −74 8 24 36 16-QAM 0.75 4 192 144 −19 −70 4 20 48 64-QAM 0.666 6 288192 −22 −66 0 16 54 64-QAM 0.75 6 288 216 −25 −65 −1 15

TABLE 5 Channelization for Table 4 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 6 2.4 GHz, 20 MHz channel BW, 192 Mbps max bit rate ST TX CodeModu- Code Rate Antennas Rate lation Rate NBPSC NCBPS NDBPS 12 2 1 BPSK0.5 1 48 24 24 2 1 QPSK 0.5 2 96 48 48 2 1 16-QAM 0.5 4 192 96 96 2 164-QAM 0.666 6 288 192 108 2 1 64-QAM 0.75 6 288 216 18 3 1 BPSK 0.5 148 24 36 3 1 QPSK 0.5 2 96 48 72 3 1 16-QAM 0.5 4 192 96 144 3 1 64-QAM0.666 6 288 192 162 3 1 64-QAM 0.75 6 288 216 24 4 1 BPSK 0.5 1 48 24 484 1 QPSK 0.5 2 96 48 96 4 1 16-QAM 0.5 4 192 96 192 4 1 64-QAM 0.666 6288 192 216 4 1 64-QAM 0.75 6 288 216

TABLE 7 Channelization for Table 6 Channel Frequency (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 8 5 GHz, 20 MHz channel BW, 192 Mbps max bit rate ST TX Code Modu-Code Rate Antennas Rate lation Rate NBPSC NCBPS NDBPS 12 2 1 BPSK 0.5 148 24 24 2 1 QPSK 0.5 2 96 48 48 2 1 16-QAM 0.5 4 192 96 96 2 1 64-QAM0.666 6 288 192 108 2 1 64-QAM 0.75 6 288 216 18 3 1 BPSK 0.5 1 48 24 363 1 QPSK 0.5 2 96 48 72 3 1 16-QAM 0.5 4 192 96 144 3 1 64-QAM 0.666 6288 192 162 3 1 64-QAM 0.75 6 288 216 24 4 1 BPSK 0.5 1 48 24 48 4 1QPSK 0.5 2 96 48 96 4 1 16-QAM 0.5 4 192 96 192 4 1 64-QAM 0.666 6 288192 216 4 1 64-QAM 0.75 6 288 216

TABLE 9 channelization for Table 8 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 10 5 GHz, with 40 MHz channels and max bit rate of 486 Mbps TX STCode Code Rate Antennas Rate Modulation Rate NBPSC 13.5 Mbps 1 1 BPSK0.5 1 27 Mbps 1 1 QPSK 0.5 2 54 Mbps 1 1 16-QAM 0.5 4 108 Mbps 1 164-QAM 0.666 6 121.5 Mbps 1 1 64-QAM 0.75 6 27 Mbps 2 1 BPSK 0.5 1 54Mbps 2 1 QPSK 0.5 2 108 Mbps 2 1 16-QAM 0.5 4 216 Mbps 2 1 64-QAM 0.6666 243 Mbps 2 1 64-QAM 0.75 6 40.5 Mbps 3 1 BPSK 0.5 1 81 Mbps 3 1 QPSK0.5 2 162 Mbps 3 1 16-QAM 0.5 4 324 Mbps 3 1 64-QAM 0.666 6 365.5 Mbps 31 64-QAM 0.75 6 54 Mbps 4 1 BPSK 0.5 1 108 Mbps 4 1 QPSK 0.5 2 216 Mbps4 1 16-QAM 0.5 4 432 Mbps 4 1 64-QAM 0.666 6 486 Mbps 4 1 64-QAM 0.75 6

TABLE 11 Power Spectral Density (PSD) mask for Table 10 PSD Mask 2Frequency Offset dBr −19 MHz to 19 MHz 0 +/−21 MHz −20 +/−30 MHz −28+/−40 MHz and −50 greater

TABLE 12 Channelization for Table 10 Frequency Frequency Channel (MHz)Country Channel (MHz) County 242 4930 Japan 250 4970 Japan 12 5060 Japan38 5190 USA/Europe 36 5180 Japan 46 5230 USA/Europe 44 5520 Japan 545270 USA/Europe 62 5310 USA/Europe 102 5510 USA/Europe 110 5550USA/Europe 118 5590 USA/Europe 126 5630 USA/Europe 134 5670 USA/Europe151 5755 USA 159 5795 USA

What is claimed is:
 1. A wireless communication device comprising: aprocessor configured to: generate a packet that includes a groupidentification field (GroupID); set a plurality of bits within theGroupID to a first value to indicate the packet is a single user (SU)packet or set the plurality of bits within the GroupID to a second valueto indicate the packet is a multiple user (MU) packet; and transmit thepacket to at least one other wireless communication device.
 2. Thewireless communication device of claim 1, wherein the processor isfurther configured to: generate another packet that includes a firstsignal (SIG) field, a second SIG field, and at least one other fieldlocated between the first SIG field and the second SIG field; setanother plurality of bits within another GroupID that is included withinthe first SIG field to the first value to indicate the another packet isanother SU packet or set the another plurality of bits within theanother GroupID of the first SIG field to the second value to indicatethat the another packet is another MU packet; and transmit the anotherpacket to at least one of the at least one other wireless communicationdevice or another wireless communication device.
 3. The wirelesscommunication device of claim 1, wherein the processor is furtherconfigured to: generate another packet that includes a signal (SIG)field; set another plurality of bits within another GroupID that isincluded within the SIG field to the first value to indicate the anotherpacket is another SU packet or set the another plurality of bits withinthe another GroupID of the SIG field to the second value to indicatethat the another packet is another MU packet; and transmit the anotherpacket to at least one of the at least one other wireless communicationdevice or another wireless communication device.
 4. The wirelesscommunication device of claim 1, wherein the processor is furtherconfigured to: generate the packet as the MU packet that includes afirst signal (SIG) field, a second SIG field, and at least one otherfield located between the first SIG field and the second SIG field,wherein the first SIG field includes first information for use by both afirst other wireless communication device and a second other wirelesscommunication device to process a first other field in the MU packet,wherein the second SIG field includes second information for use by atleast one of the first other wireless communication device or the secondother wireless communication device to process a second other field inthe MU packet.
 5. The wireless communication device of claim 1, whereinthe processor is further configured to: generate the packet to include afirst signal (SIG) field, a second SIG field, and at least one otherfield located between the first SIG field and the second SIG field;transmit the first SIG field using omni-directional transmission; andtransmit the second SIG field using beamforming transmission.
 6. Thewireless communication device of claim 1, wherein the processor isfurther configured to: generate the packet to include a first shorttraining field (STF), followed by a first long training field (LTF),followed by a first signal field (SIG) field that includes the GroupID,followed by a second STF, followed by a second LTF, followed by a secondSIG field, followed by a data field.
 7. The wireless communicationdevice of claim 1 further comprising: an access point (AP), wherein theat least one other wireless communication device includes a wirelessstation (STA).
 8. The wireless communication device of claim 1 furthercomprising: a wireless station (STA), wherein the at least one otherwireless communication device includes an access point (AP).
 9. Awireless communication device comprising: a processor configured to:receive a packet from another wireless communication device; andinterpret a group identification field (GroupID) of the packet todetermine whether the packet is a single user (SU) packet or a multipleuser (MU) packet including to determine that the packet is the SU packetwhen a plurality of bits within the GroupID is set to a first value andto determine that the packet is the MU packet when the plurality of bitswithin the GroupID is set to a second value.
 10. The wirelesscommunication device of claim 9, wherein the processor is furtherconfigured to: receive another packet from the another wirelesscommunication device; process the another packet to identify a firstsignal (SIG) field that includes another GroupID, a second SIG field,and at least one other field located between the first SIG field and thesecond SIG field within the another packet; and interpret the anotherGroupID to determine whether the another packet is another SU packet oranother MU packet including to determine that the another packet is theanother SU packet when another plurality of bits within the anotherGroupID is set to the first value and to determine that the anotherpacket is the another MU packet when the another plurality of bitswithin the another GroupID is set to the second value.
 11. The wirelesscommunication device of claim 9, wherein the processor is furtherconfigured to: receive a first signal (SIG) field of the packet viaomni-directional transmission; and receive a second SIG field of thepacket via beamforming transmission, wherein the packet includes thefirst SIG field, the second SIG field, and at least one other fieldlocated between the first SIG field and the second SIG field.
 12. Thewireless communication device of claim 9, wherein the processor isfurther configured to: process the packet to identify a first shorttraining field (STF), followed by a first long training field (LTF),followed by a first signal field (SIG) field that includes the GroupID,followed by a second STF, followed by a second LTF, followed by a secondSIG field, followed by a data field within the packet.
 13. The wirelesscommunication device of claim 9 further comprising: a wireless station(STA), wherein the another wireless communication device includes anaccess point (AP).
 14. A method for execution by a wirelesscommunication device, the method comprising: generating a packet thatincludes a group identification field (GroupID); setting a plurality ofbits within the GroupID to a first value to indicate the packet is asingle user (SU) packet or setting the plurality of bits within theGroupID to a second value to indicate the packet is a multiple user (MU)packet; and transmitting, via a communication interface of the wirelesscommunication device, the packet to at least one other wirelesscommunication device.
 15. The method of claim 14 further comprising:generating another packet that includes a first signal (SIG) field, asecond SIG field, and at least one other field located between the firstSIG field and the second SIG field; setting another plurality of bitswithin another GroupID that is included within the first SIG field tothe first value to indicate the another packet is another SU packet orsetting the another plurality of bits within the another GroupID of thefirst SIG field to the second value to indicate that the another packetis another MU packet; and transmitting, via the communication interfaceof the wireless communication device, the another packet to at least oneof the at least one other wireless communication device or anotherwireless communication device.
 16. The method of claim 14 furthercomprising: generating another packet that includes a signal (SIG)field; setting another plurality of bits within another GroupID that isincluded within the SIG field to the first value to indicate the anotherpacket is another SU packet or setting the another plurality of bitswithin the another GroupID of the SIG field to the second value toindicate that the another packet is another MU packet; and transmitting,via the communication interface of the wireless communication device,the another packet to at least one of the at least one other wirelesscommunication device or another wireless communication device.
 17. Themethod of claim 14 further comprising: generating the packet as the MUpacket that includes a first signal (SIG) field, a second SIG field, andat least one other field located between the first SIG field and thesecond SIG field, wherein the first SIG field includes first informationfor use by both a first other wireless communication device and a secondother wireless communication device to process a first other field inthe MU packet, wherein the second SIG field includes second informationfor use by at least one of the first other wireless communication deviceor the second other wireless communication device to process a secondother field in the MU packet.
 18. The method of claim 14 furthercomprising: generating the packet to include a first signal (SIG) field,a second SIG field, and at least one other field located between thefirst SIG field and the second SIG field; transmitting, via thecommunication interface of the wireless communication device, the firstSIG field using omni-directional transmission; and transmitting, via thecommunication interface of the wireless communication device, the secondSIG field using beamforming transmission.
 19. The method of claim 14further comprising: generating the packet to include a first shorttraining field (STF), followed by a first long training field (LTF),followed by a first signal field (SIG) field that includes the GroupID,followed by a second STF, followed by a second LTF, followed by a secondSIG field, followed by a data field.
 20. The method of claim 14, whereinthe wireless communication device is an access point (AP), and the atleast one other wireless communication device includes a wirelessstation (STA).